A web browser is a software application that enables a user to display and interact with text, images, video and other information typically located on a web page at a website on the World Wide Web or a local area network. Text and images on a web page can contain hyperlinks to other web pages at the same or different websites. Web browsers allow a user to quickly and easily access information provided on many web pages at many websites by traversing these links. Web browsers available for personal computers include Safari, Internet Explorer, Firefox, Netscape, and Opera.
The file format for a web page is usually hyper-text markup language (HTML) and is transferred with a hyper-text transfer protocol (HTTP). Most browsers natively support a variety of formats in addition to HTML, such as the extensible markup language (XML) and image formats, and can be extended to support more through the use of plug-ins. The combination of HTML content type and uniform resource locator (URL) specification allows web page designers to embed images, animations, video, sound, and streaming media into a web page, or to make them accessible through the web page. A style sheet language such as cascading style sheets (CSS) may be used to describe the presentation of a document written in a markup language. CSS is used by both the authors and readers of web pages to define colors, fonts, layout, and other aspects of document presentation. CSS is designed to enable the separation of document content written in a markup language from document presentation written in CSS.
A typical web browser of the prior art retrieves a data stream of web content expressed in a markup language and analyzes components or elements of the data stream which can be a web page. The web browser builds a data structure in the form of a logic tree with nodes. Each node has a height, width, position, and order on the web page. The nodes of the data structure are rendered as an image into a backing store located in main memory. Rendering is the process of generating an image from a model, by means of software programs. The model is a description of objects in a strictly defined language or data structure. The render process consumes substantial processing and memory resources located in main memory.
A data stream may have dynamic content that changes based on user input, JavaScript code execution, video updating or for other reasons. For example, a component of a data stream may be modified, moved, resized, animated or changed in some way. A component being moved creates “damage” to content in its wake that requires other components to be redrawn. A web browser displaying a web page with dynamic content would need to re-render the entire logic tree or at least the components damaged by the move. The re-rendering process consumes processing and memory resources located on a computer. Also, the re-rendering process requires additional time and slows the performance of the web browser.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.